Open redirect: xfinity.com

name: "Open redirect: xfinity.com"
description: |
  Message contains use of the xfinity.com open redirect. This has been exploited in the wild.
type: "rule"
severity: "medium"
source: |
    type.inbound
    and any(body.links,
            .href_url.domain.root_domain == "xfinity.com"
            and strings.icontains(.href_url.path, "/learn/cima/login")
            and strings.icontains(.href_url.query_params, "referer=")
            and not regex.icontains(.href_url.query_params,
                                    'referer=(?:https?)?(?:(?:%3a|\:)?(?:\/|%2f){2})?xfinity\.com+'
            )
    )
    and not sender.email.domain.root_domain in ("xfinity.com", "comcast.net")
    
    // negate highly trusted sender domains unless they fail DMARC authentication
    and (
      (
        sender.email.domain.root_domain in $high_trust_sender_root_domains
        and not headers.auth_summary.dmarc.pass
      )
      or sender.email.domain.root_domain not in $high_trust_sender_root_domains
    )
attack_types:
  - "Credential Phishing"
  - "Malware/Ransomware"
tactics_and_techniques:
  - "Open redirect"
detection_methods:
  - "Sender analysis"
  - "URL analysis"
id: "7b9012fa-0f14-57d5-b729-cb3b84565c47"